diff --git a/p4app/controller.py b/p4app/controller.py
index 27308c6..86dd230 100755
--- a/p4app/controller.py
+++ b/p4app/controller.py
@@ -322,7 +322,7 @@ class L2Controller(object):
             dev    = "{}-eth0".format(host)
             net    = v4route['net']
             ipaddr = "{}/{}".format(net[1],net.prefixlen)
-            router = self.ipv4_router(net)
+            router = str(self.ipv4_router(net))
 
             self.config_v4_host(host, str(net), str(ipaddr), dev, router)